Electromagnetic fuel injection spray valve

ABSTRACT

The nozzle valve needle is closed by a compression spring housed in a space that is separate from the space in which the pressure determines the opening and closing of the needle. In another embodiment, a piston is acted upon by the pressure in this latter space to close the needle.

United States Patent [72] Inventor Robert Huber [50] Field of Search239/86, 87, Zumikon, Switzerland 88, 89, 90, 91, 92, 95, 96, 533, 585[21] Appl. No. 844,005 [22] Filed July 23, 1969 References Clted [45]Patented Oct. 5, 1971 UNlTED STATES PATENTS [73] Assignee Societe DesProcedes DInjection Sopromi 3,464,627 9/l969 Huber n 239/96 P k g rgg3,481,542 12/1969 Huber 239 71 I II y Swigtzerland Primary ExaminerM.Henson Wood, Jr. [31] 911/68 Assistant Examiner-Edwin D. GrantAttorney-Spencer & Kaye [54] ELECTROMAGNETIC FUEL INJECTION SPRAY VALVEABSTRACT: The nozzle valve needle is closed by a compres- Clams 4 D'awmgsion spring housed in a space that is separate from the space in [52]U.S. Cl 239/96, which the pressure determines the opening and closing ofthe 239/533, 239/585 needle. in another embodiment, a piston is actedupon by the [51] Int. Cl .,F02m 47/00 pressure in this latter space toclose the needle.

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Mlo'rmys ELECTROMAGNETIC FUEL INJECTION SPRAY VALVE BACKGROUND OF THEINVENTION The invention relates to an electromagnetic fuel-injectionspray valve for internal combustion engines, particularly dieselengines, including an electromagnetic metering valve at the upper end ofthe spray valve body, a spray nozzle, a needle valve arrangedimmediately upstream of the spray nozzle, and a nozzle valve needleincorporated by the needle valve and opened by the fall in the pressureacting on the needle, caused when the metering valve opens to establisha path to a fuel return line.

An injection valve of this kind is prior art, the quantity of the fuelinjected being determined by the length of the current pulse fed to theelectromagnetic metering valve.

A spring closes the nozzle valve needle after each injection. Thisspring is contained in a space the fuel pressure in which determines theopening and closing of the nozzle valve needle by the spring, the spacebeing connected to a relief line. As a consequence of the additionalvolume required by this space to house the spring, the total volume isrelatively large in which the fuel pressure must be reduced for eachinjection. This fact slows down the rise and fall of the fuel pressurein this space, and delays control of the engine, particularly at highr.p.m.

SUMMARY OF THE INVENTION BRIEF DESCRIPTION OF THE DRAWINGS Severalembodiments of the invention will be described,

with reference to the figures of the accompanying drawings, wherein:

FIGS. I 2, and 3 are longitudinal sections of three differentembodiments of the invention; and

FIG. 4 is a modification of the embodiment shown in FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS With reference to FIG. 1, theelectromagnetic part of the valve comprises in a known manner a core 1having a winding 2 and a movable armature 3, which is rigidly connectedto the needle 4 of a metering valve. The needle cooperates with thevalve seat 5. A compression spring 24 presses the armature downwards,seating the metering needle 4 on its seat 5. The upper end of the spring24 presses against a stop 25 slidably held in the armature 3 and pressedagainst the core 1. A rod 7 is sealingly held in the valve body 6 freeto slide axially. Joined to the lower end of the rod 7 is a nozzle valveneedle 8, which cooperates with the valve seat 9 and forms the actualinjection spray valve controlling the flow of fuel to the spray nozzle10. A compression spring 12, located in a chamber 11, presses on the rod7 and hence on the nozzle valve needle 8 to keep the injection sprayvalve closed.

The fuel, delivered by a high-pressure supply pump, flows through theline 13 and the bores 14 and 15 to be delivered simultaneously to thechamber 11 and the space 16 just upstream of the seat 9.

The bore 15 is connected to an annular space 17, which a throttling bore18 connects to bores 19 that form a relief line connecting a space 20above the nozzle valve needle 8 with the valve seat 5 of the meteringvalve 4 and 5. When the latter is open the space 20 communicates with aspace 21 that a bore 22 connects with a return line 23, in which thefuel is at approximately atmospheric pressure. The fuel flows throughbores (not shown) in the core I to the return line 23. The injectionspray valve operates in the following manner. The fuel delivered underpressure by the line 13 flows through the bores 14 and 15 to fill thespaces 11, I6, and I7, and through the throttling bore 18 into therelief line I9 and the space 20. When a current pulse energizes thewinding 2, the armature 3 and its metering needle 4 are raised, thepressure in the relief line 19 and the space 20 consequently falling.Since the crosssectional area of the nozzle valve needle 8 is greaterthan that of the rod 7, the needle 8 is raised from its seat 9 and fuelsprayed from the spray nozzle 10 into the cylinder, not shown. As soonas-the flow of current in the winding 2 stops, the me tering needle 4closes. The spring 12 presses the nozzle valve needle 8 back onto itsseat 9, and at the same time the pressure in the relief line 19 and thespace 20 rises.

In the embodiment shown in FIG. 2, a piston 28 is arranged above a rod27, which corresponds to the rod 7 in FIG. I. The rod 27 is arrangedwith lateral play in the valve body 6. The space 29 above the injectionspray needle 8 is connected to a space 30, which a passage 31 and a bore32 connect to a space 34, and which a bore 33 and passages in the core 1connect to the return line 23, so that an approximately atmosphericpressure is present in all of these spaces and connecting bores andpassages.

Fuel delivered under high pressure by the line 3 flows through the bores35 into the space 36 and through the throttling bore 37 into the space38 above the piston 28. When the winding 2 is energized, the meteringneedle 4 is raised, causing the high pressure in the space 38 to fall.As a consequence of the high pressure in the space 36, the injectionspray needle 8 is raised from its seat 9, and fuel sprays from the spraynozzle 10 into the cylinder, not shown. The space 38, which must berelieved of its pressure for each injection, has in this embodiment avery small volume. As soon as the metering needle 4 is again seated, thespring 12 reseats the needle 8, and the pressure in the space 38 rises.

In the embodiment shown in FIG. I, the spring 12 is the only means forclosing the needle 8, whereas in the embodiment shown in FIG. 2 thespring 12 can be eliminates or can be weak, provided that the piston 28has a somewhat larger diameter than does the shaft of the needle 8, sothat the downward closing force acting on the piston 28 is greater thanthe upward force acting on the needle 8.

In the embodiment shown in FIG. 3 is closing spring 12 is also notessential. A piston 40, having a larger cross section than doesinjection spray needle 8, is arranged immediately above the needle 8.The fuel delivered at high pressure by the line 13 flows through thebores 41 to the space 42 and through the throttling bore 43 and the bore44 into the space 45.

In contrast to the first embodiment, the space 46 between the piston 40and the injection spray needle 8 is connected at all times to a space 48by the bores 47 and to the return line 23 by a bore 49 and the passages(not shown) in the core I. As a consequence of the greater crosssectional surface area of the piston 40, the latter exerts a closingforce on the needle 8. As soon, however, as the energized winding 2opens the metering valve 4 and 5, the pressure in the space 45 falls;and the injection spray needle 8, because of the unchanged pressure inthe space 42, is raised, and fuel is sprayed from the nozzle 10. Whenthe metering valve 4 and 5 closes, the pressure in the space 45immediately rises, and the piston 40 presses the needle 8 back onto itsseat 9.

In order to keep the needle 8 seated when the fuel pressure is absent(engine shut off) there can be incorporated in the piston 40, as shownin FIG. 4, a weak spring 50, which presses against the needle 8 by meansof an auxiliary piston SI.

In the three embodiments the spaces 20, 38, and 45, the relativepressure in which determines the opening and closing of the injectionspray valve, are connected by the calibrated throttling bores 18, 37,and 43 to the fuel supply line 13 and are connected directly, or by thebores 19 and 44, with the electromagnetically controlled metering valve4 and 5. The dimensions'of the calibrated cross section and of the crosssection exposed by the valve fundamentally influence the manner in whichthe spray valve 8 and 9 opens and closes. If the calibrated inlet ismade relatively large as compared to the cross section controlled by thevalve, for example, the needle 8 opens relatively slowly, since the fuelthat must be pushed away by the needle 8 (FIG. 1), or by the piston 28or 40 (FIGS. 2 and 3), cannot quickly escape. But the valve closesquickly because of the large inlet cross section.

On the other hand, if the inlet cross section is small and the valvecross section large, the valve opens quickly but closes much moreslowly.

By suitable choice of the cross sections through which the fuel flows,the fuel injection spray valve can be adapted to the engine.

Although the preferred embodiments of the invention have been described,the scope of, and the breadth of protection afforded to, the inventionare limited solely by the appended claims.

I claim:

1. An electromagnetic fuel-injection spray valve for internal combustionengines, particularly diesel engines, including an electromagneticmetering valve (4,5) at the upper end of the spray valve body (16), aspray nozzle a needle valve (8,9) arranged immediately upstream of saidspray nozzle, a nozzle valve needle (8) incorporated by said needlevalve and opened by the fall in the pressure acting on said needle,caused when said metering valve opens to establish a path to a fuelreturn line (23), and wherein the improvement comprises a first space(20,38,45) in which the fuel pressure determines the opening and closingof said nozzle valve needle, and means operatively associated with saidnozzle valve needle for aiding the closing of said nozzle valve needlein response to the closing of the metering valve.

2. The injection spray valve as defined in claim 1, wherein said firstspace is provided with an inlet passage for the inflow of fuel theretoand is connected to said metering valve to form part of the path to thefuel return line, and the cross section of the fuel flowing into saidfirst space via said inlet passage is smaller than that of the fuelflowing thereout vial said return line path, for obtaining a quickopening and a slow closing of said nozzle valve needle.

3. The injection spray valve as defined in claim 1, wherein said firstspace is provided with an inlet passage for the inflow of fuel theretoand is connected to said metering valve to form part of the path to thefuel return line, and the cross section of the fuel flowing into saidfirst space via said inlet passage is greater than that of the fuelflowing thereout via said return line path, for obtaining a slow openingand a quick closing of said nozzle valve needle.

4. The injection spray valve as defined in claim 1, wherein said meansoperatively associated with said nozzle valve needle comprise: a secondspace separate from said first space, and spring means contained withinsaid second space for aiding the closing of said nozzle valve needle.

5. The injection spray valve as defined in claim 4, wherein said nozzlevalve needle is closed by said spring means, said second space (11) isunder fuel pressure at all times, and said first space is located at therear end of said nozzle valve nee dle, and further including a rod (7)sealingly arranged in the spray valve body (6) and free to slide axiallyfor transmitting the force of said spring means to said nozzle valveneedle.

6. The injection spray valve as defined in claim 4, wherein said nozzlevalve needle is closed by said spring means, said second space (30) isrelieved of fuel pressure at all times, and said first space (38) is indirect communication with said metering valve at all times, and furtherincluding a rod (27) free to move axially for transmitting the force ofsaid spring means to said nozzle valve needle, and a piston (28)connected to said rod to move therewith, one end of said piston definingone side of said first space.

7. The injection spray valve as defined in claim 4, wherein said nozzlevalve needle is in part closed by said spring means, said second space(30) is relieved of fuel pressure at all times,

and said first space (3!!) is in direct communication with said meteringvalve at al times, and further including a rod (27) free to move axiallyfor transmitting the force of said spring means to said nozzle valveneedle, and a piston (28) connected to said rod to move therewith, saidpiston having a larger diameter than does the shaft of said nozzle valveneedle to help to close the latter, and one end of said piston definingone side of said first space.

8. An electromagnetic fuel-injection spray valve as defined in claim 1wherein said means operatively associated with said nozzle valve needlecomprised closing means operated by the pressure in said first space forclosing said nozzle valve needle.

9. The injection spray valve as defined in claim 8, wherein said nozzlevalve needle is closed by said closing means and said closing means is apiston (28) of which one end defines one side of said first space, andsaid first space is in direct communication with said metering valve atall times, and further including a rod (27) free to move axially fortransmitting the pressure within said first space acting on said pistonto said nozzle valve needle to close the latter.

10. The injection spray valve as defined in claim 8, wherein said nozzlevalve needle is closed by said closing means and the latter is anoperating piston (40) of which one end defines one side of said firstspace (45 said operating piston having a cross section greater than doessaid nozzle valve needle and acting directly on the latter, whereby thefuel pressure in said first space determines the closing of said nozzlevalve needle.

11. The injection spray valve as defined in claim 10, including anauxiliary piston (51) arranged within said operating piston for actingon said nozzle valve needle, and a compression spring (50) pressing onsaid auxiliary piston to keep said nozzle valve needle closed when thefuel pressure is absent.

1. An electromagnetic fuel-injection spray valve for internal combustionengines, particularly diesel engines, including an electromagneticmetering valve (4,5) at the upper end of the spray valve body (16), aspray nozzle (10), a needle valve (8,9) arranged immediately upstream ofsaid spray nozzle, a nozzle valve needle (8) incorporated by said needlevalve and opened by the fall in the pressure acting on said needle,caused when said metering valve opens to establish a path to a fuelreturn line (23), and wherein the improvement comprises a first space(20,38,45) in which the fuel pressure determines the opening and closingof said nozzle valve needle, and means operatively associated with saidnozzle valve needle for aiding the closing of said nozzle valve needlein response to the closing of the metering valve.
 2. The injection sprayvalve as defined in claim 1, wherein said first space is provided withan inlet passage for the inflow of fuel thereto and is connected to saidmetering valve to form part of the path to the fuel return line, and thecross section of the fuel flowing into said first space via said inletpassage is smaller than that of the fuel flowing thereout vial saidreturn line path, for obtaining a quick opening and a slow closing ofsaid nozzle valve needle.
 3. The injection spray valve as defined inclaim 1, wherein said first space is provided with an inlet passage forthe inflow of fuel thereto and is connected to said metering valve toform part of the path to the fuel return line, and the cross section ofthe fuel flowing into said first space via said inlet passage is greaterthan that of the fuel flowing thereout via said return line path, forobtaining a slow opening and a quick closing of said nozzle valveneedle.
 4. The injection spray valve as defined in claim 1, wherein saidmeans operatively associated with said nozzle valve needle comprise: asecond space separate from said first space, and spring means containedwithin said second space for aiding the closing of said nozzle valveneedle.
 5. The injection spray valve as defined in claim 4, wherein saidnozzle valve needle is closed by said spring means, said second space(11) is under fuel pressure at all times, and said first space islocated at the rear end of said nozzle valve needle, and furtherincluding a rod (7) sealingly arranged in the spray valve body (6) andfree to slide axially for transmitting the force of said spring means tosaid nozzle valve needle.
 6. The injection spray valve as defined inclaim 4, wherein said nozzle valve needle is closed by said springmeans, said second space (30) is relieved of fuel pressure at all times,and said first space (38) is in direct communication with said meteringvalve at all times, and further including a rod (27) free to moveaxially for transmitting the force of said spring means to said nozzlevalve needle, and a piston (28) connected to said rod to move therewith,one end of said piston defining one side of said first space.
 7. Theinjection spray valve as defined in claim 4, wherein said nozzle valveneedle is in part closed by said spring means, said second space (30) isrelieved of fuel pressure at all times, and said first space (38) is indirect communication with said metering valve at all times, and furtherincluding a rod (27) free to move axially for transmitting the force ofsaid spring means to said nozzle valve needle, and a piston (28)connected to said rod to move therewith, said piston having a largerdiameter than does the shaft of said nozzle valve needle to help toclose the latter, and one end of said piston defining one side of saidfirst space.
 8. An electromagnetic fuel-injection spray valve as definedin claim 1 wherein said means operatively associated with said nozzlevalve needle comprised closing means operated by the pressure in saidfirst space for closing said nozzle valve needle.
 9. The injection sprayvalve as defined in claim 8, wherein said nozzle valve needle is closedby said closing means and said closing means is a piston (28) of whichone end defines one side of said first space, and said first space is indirect communication with said metering valve at all times, and furtherincluding a rod (27) free to move axially for transmitting the pressurewithin said first space acting on said piston to said nozzle valveneedle to close the latter.
 10. The injection spray valve as defined inclaim 8, wherein said nozzle valve needle is closed by said closingmeans and the latter is an operating piston (40) of which one enddefines one side of said first space (45), said operating piston havinga cross section greater than does said nozzle valve needle and actingdirectly on the latter, whereby the fuel pressure in said first spacedetermines the closing of said nozzle valve needle.
 11. The injectionspray valve as defined in claim 10, including an auxiliary piston (51)arranged within said operating piston for acting on said nozzle valveneedle, and a compression spring (50) pressing on said auxiliary pistonto keep said nozzle valve needle closed when the fuel pressure isabsent.